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