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