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