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