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