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