One vertex per element, one color per generator, with an edge from x to x·s.
(1,2)(3,4)(5,6)(7,8)(9,10)(11,14)(12,20)(13,16)(15,21)(17,19)(18,23)(22,24)(25,26,30,29)(27,31,35,34)(28,36,38,32)(33,40,37,39)(2,6)(4,7)(9,10)(11,17)(12,20)(13,16)(14,19)(15,21)(18,22)(23,24)(26,29)(31,34)(32,36)(39,40) involution — undirected(2,6)(3,8)(9,10,13,16)(11,17,19,14)(12,15,21,20)(18,23,24,22)(25,27,30,35)(26,31,29,34)(28,37,38,33)(32,40,36,39)(1,3,5,8)(2,7,6,4)(9,10)(11,14)(12,15)(13,16)(17,19)(18,22)(20,21)(23,24)(25,28,30,38)(26,32,29,36)(27,33,35,37)(31,39,34,40)(1,2)(3,7)(4,8)(5,6)(9,11)(10,14)(12,18)(13,19)(15,22)(16,17)(20,23)(21,24)(25,27)(26,31)(28,33)(29,34)(30,35)(32,39)(36,40)(37,38) involution — undirected(1,4,5,7)(2,8,6,3)(9,12)(10,15)(11,18)(13,21)(14,22)(16,20)(17,23)(19,24)(25,29,30,26)(27,34,35,31)(28,36,38,32)(33,40,37,39)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.