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