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)(11,14)(12,15)(13,16)(17,21)(18,22)(19,23)(20,24)(25,26,30,35)(27,33,38,39)(28,34,29,32)(31,36,40,37)(9,11)(10,14)(12,19)(13,18)(15,23)(16,22)(17,20)(21,24)(25,27,30,38)(26,31,35,40)(28,37,29,36)(32,33,34,39)(1,3,5,4)(2,6,7,8)(9,12,13,20)(10,15,16,24)(11,17,18,19)(14,21,22,23)(25,28,30,29)(26,32,35,34)(27,36,38,37)(31,39,40,33)(11,18)(14,22)(17,19)(21,23)(25,27)(26,33)(28,36)(29,37)(30,38)(31,32)(34,40)(35,39) involution — undirected(1,4,5,3)(2,6,7,8)(10,16)(14,22)(15,24)(21,23)(25,28,30,29)(26,32,35,34)(27,37,38,36)(31,33,40,39)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.