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