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