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