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