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