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