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