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