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