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