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