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