One vertex per element, one color per generator, with an edge from x to x·s.
(1,2)(3,7)(4,5)(6,8)(9,10)(11,14)(12,16)(13,17)(15,18)(19,22)(20,21)(23,24)(25,26)(27,36)(28,33)(29,32)(30,34)(31,35)(37,38)(39,40) involution — undirected(1,3)(2,6)(4,7)(5,8)(9,11)(10,14)(12,19)(13,18)(15,17)(16,22)(20,23)(21,24)(25,27,31,29)(26,32,35,36)(28,37,34,39)(30,38,33,40)(1,3)(2,6)(4,7)(5,8)(11,18)(14,15)(19,24)(22,23)(25,28,31,34)(26,33,35,30)(27,37,29,39)(32,40,36,38)(3,8)(6,7)(9,11)(10,15)(12,19)(13,18)(14,17)(16,23)(20,22)(21,24)(25,28)(26,33)(27,37)(29,39)(30,35)(31,34)(32,40)(36,38) involution — undirected(1,4,5,2)(3,7,8,6)(9,12)(10,16)(11,19)(13,21)(14,22)(15,23)(17,20)(18,24)(25,29,31,27)(26,32,35,36)(28,39,34,37)(30,38,33,40)(1,3)(2,7)(4,6)(5,8)(9,10)(11,14)(12,20)(13,17)(15,18)(16,21)(19,23)(22,24)(25,30,31,33)(26,34,35,28)(27,38,29,40)(32,39,36,37)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.