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