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