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