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