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