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