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