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