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