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