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