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