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