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