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