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