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