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