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