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