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