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