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